The present invention relates to improved processes for the production of secondary alkyl indanes, particularly mixtures of 1,1,3,5-tetramethyl-3-isopropylindane (IPI) and 1,3,3,5-tetramethyl-1-isopropylindane, and improved processes for the production of alkylated tetrahydronaphthalenes, particularly mixtures of 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (HMT) and 1,1,2,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene.
Alkylated indanes such as IPI and alkylated tetrahydronaphthalenes such as HMT are of significant importance to the perfumery as well as other industries. By conventional acylation processes, IPI, for example, can be converted to 7-acetyl-1,1,3,5-tetramethyl-3-isopropyl-indane, a well-known musk perfume ingredient. Similarly, HMT can be transformed to 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene, also a widely recognized musk perfume ingredient. Because of their clean musk fragrance and ability to retain that fragrance over long periods of time, such IPI and HMT derivatives are of great commercial value as synthetic musk perfume substitutes for the expensive, natural musk perfumes of the macrocyclic ketone series. Consequently, various synthetic methods have been proposed for the production of IPI and HMT, as well as other related compounds useful in the perfumery or other industries.
Much research emphasis has been placed on the production of HMT-type compounds. For example, Frank, U.S. Pat. Nos. 4,877,910, 4,877,911, 4,877,912, 4,877,913, 4,877,914, 4,877,915 and 4,877,916, describes processes for producing polyalkyl tetrahydronaphthalene compounds comprising contacting partially substituted benzene compounds such as para-cymene with an olefinic compound such as neohexene or 2,3-dimethyl-1-butene in the presence of one or more of such reagents as alkyl halides or hydrogen halides, Lewis acids, phase transfer agents and hydride abstracting agents.
Wood et al., U.S. Pat. No. 3,856,875, discuss a process for the preparation of HMT wherein an equivalent or excess amount of para-cymene is reacted with a substantially equal molar solution of neohexene and a tertiary alkyl halide in the presence of an effective amount of an anhydrous aluminum halide catalyst suspended in a reaction-compatible solvent.
Wood, U.S. Pat. No. 3,246,044, discloses a process for preparing HMT which includes reacting an alpha,para-dimethylstyrene derivative such as dimethylpara-tolyl-carbinyl halide and neohexene in the presence of a catalyst such as aluminum chloride at low temperatures.
Sato et al., U.S. Pat. No. 4,284,818, describe a process for producing HMT comprising reacting paracymene with a 2,3-dimethylbutene using a catalytic amount of anhydrous aluminum halide in the presence of a secondary alkyl halide, tertiary alkyl halide, propargyl halide or allyl halide.
Japanese Patent Publication SHO 57-40420 discusses a method of making HMT characterized by reacting para-cymene and neohexene in the presence of anhydrous aluminum halide as catalyst.
Kahn, U.S. Pat. No. 3,379,785, relates to a process for preparing polyalkyltetrahydronaphthalenes, more specifically, a process for preparing HMT, which involves the reaction of a substituted styrene and a 2,3-dimethylbutene, said reaction being carried out at elevated temperatures and in the presence of a cation exchange resin.
Suzukamo et al., U.S. Pat. No. 4,767,882, disclose a process for preparing a tetrahydronaphthalene derivative in an optically active state which comprises reacting a benzene compound and a pyrocine compound in the presence of a Lewis acid, or, alternatively, reacting a benzene with the pyrocine compound in the presence of an acid catalyst followed by treatment of the resultant production with the Lewis acid.
Some researchers have also focused on the production of IPI-type compounds. For example, Sprecker et al., U.S. Pat. No. 4,466,908, describe a process for preparing indanes such as IPI comprising rearranging hexamethyltetrahydronaphthalene compounds with an aluminum chloride catalyst wherein the reaction is carried out in the presence of tetrachloroethylene solvent saturated with aluminum chloride and in the presence of an excess of aluminum chloride.
Cobb, U.S. Pat. No. 4,551,573, discloses a process for the alkylation of aromatic compounds with olefinic compounds in the presence of a catalyst consisting essentially of aluminum halide and elemental iodine.
Khalaf et al., J. Oro. Chem., Vol. 37, No. 26, pp. 4227-4235 (1972) describes Friedel-Crafts cyclialkylations of certain mono-phenol-substituted and diphenyl-substituted alcohols and alkyl chlorides to produce indane and tetralin compounds. The article also describes the isomerization of tetralins to other tetralin isomers in the presence of aluminum chloride.
Many of these prior art processes suffer from various drawbacks, such as, for example, sluggish reaction rates and high catalyst requirements. New and/or better processes for the production of these compounds are needed. The present invention is directed to these important ends.